Introduction

4. What are the Main Arguments for Evolution?

It would be exceedingly difficult to summarize all of the
arguments for evolution in a concise fashion here. However, the
most important point to remember is that evolution theory, like all
scientific theories, was originally a solution to a problem.
What's remarkable about anti-evolution propaganda is that it
never acknowledges this fact, and so never takes on the burden of
producing a better explanation for that original
problem.

So what was this original problem that evolution theory was
invented to solve? It's called the Linnaean Taxonomy, named
after Carl Linnaeus (1707-1778). If you are not familiar with the
term, it is the categorizations of plant and animal species into a
hierarchical structure. This structure has 7 layers: Kingdom,
Phylum, Class, Order, Family, Genus, and Species. Now, the
remarkable thing about this system is that the early naturalists
classified animals into a hierarchical "family tree"
structure long before the theory of evolution was proposed.
In other words, all naturalists agreed long before Darwin that the
animal kingdom appeared to be a family tree.

Now the question becomes: why did they do that? The theory of
evolution did not exist yet, so they obviously didn't do it to
please "evolutionists", as creationists are wont to call
them. What was their reasoning? Well here's where we run into
an interesting coincidence in the animal kingdom: the appearance
and development of animal features also looks like a family
tree. In other words, you can take any given feature and trace its
appearance, in various levels of complexity, along lines of animal
species. Sometimes a feature will change in one direction for one
branch of the tree and another direction for the other branch of
the tree, and as you examine more complex organisms on any given
branch, the two diverging features always (I must repeat this:
ALWAYS) stay that way. They never jump back and forth; while
features can jump between bacteria due to genetic material exchange
(they're so small that they can literally swap pieces of DNA),
we have never observed a feature exchange between complex
organisms. There is no reason why an engineer would steadfastly
refuse to take features from one product line and use them in
another, so why would this be the case for an engineered
biosystem?

This is a classic example of a problem in need of a solution. It
is not enough to classify it as coincidence, not when it is so
incredibly consistent. And the problem gets worse: when
those early naturalists examined the geographical distribution of
the animal kingdom's "family tree", they discovered
yet another impossibly unlikely "coincidence": species
which appeared to be very close to one another on the family tree
were also geographically close to one another. And whenever
someone found what appeared to be an exception to this rule, they
discovered a migratory path. Centuries later, the rule is
unchanged: when species show a biological connection, they also
show a geographical connection.

The significance of these two intertwined globe-spanning
coincidences cannot be overstated: it was an enormous
problem for taxonomy. If someone had indeed designed and created
these species, he went to enormous lengths to make them appear to
be related, by carefully arranging their structures and
geography to match! Why would he do this? There was no intrinsic
need for this, as we have proven in the last century
by artificially moving species outside their natural habitat and
seeing that in many cases, they thrive in far-off environments.
There was no intrinsic need for features to be arranged in a
hierarchical fashion, or for structural proximity to invariably
mirror geographical proximity. So why would the designer do this?
No one ever provided an answer ... until Darwin.

This, then, is the single largest argument for evolution: it
is a solution to a problem that no other theory can explain.
Creationists often try to argue that God could have chosen to make
the animal kingdom look that way, but they can't explain
why or how. And if they can't explain why or how,
then they actually do not have an explanation. Can anyone
explain how you would derive the prediction of a "family
tree" animal kingdom from the idea of God? It's not enough
to say that God reused previous designs; that would explain the
similarities but not the divisions in the family tree. The
Linnaean taxonomy is a family tree, not a family sponge. Only
evolution offers a real explanation: the kind of explanation where
you can start from its mechanism and use it to logically work
forward to predict the outcome.